Identification of differences in virulence factors production from mutant isolates of clinical Vibrio cholerae S

Abstract

Antibiotic resistant mutants for rifampicin, streptomycin and klindamycin were isolated from the clinical isolate of Vibrio choleraeS mutated by chemical mutagens. Mutation frequency of V. cholerae S depends on the treatment time and the highest viable count of antibiotic resistant were for Rifampicin after treatment with Acridine orange, Ethedium bromide, Nitrosoguanidine, 5-Florouracil, 2-Bromouracil and cyclophosphamide. One thousand mutant isolates were examined for morphological differences in colony surface, color and diameter. The treatment with AO, NTG, 5-FU, and 2-BU gave opaque to orange color larger diameter about 5-7 mm of Rifampicin resistant mutant isolates at TSA and 25% of these mutant appeared as wrinkled surface. Klindamycin resistant mutants of V. cholerae S were appeared as similar to the wild type while, Streptomycin resistant mutants of appeared as pin- point white smooth colonies on TSA. No differences were seen for oxidase, string test and fermentation pattern for sucrose and lactose. Toxin CoregulatedPili production was differed from high level order designated as +++ to mild ++ and low level designated as + after mutation with 5-FU and 2-BU. However, 15% of rifampicin resistant mutant isolates gave no agglutination phenomena. No proteases activity detected even after 48 hour of incubation; the production of lipases enzyme did not affected; while, mutator isolates produced high level of β- haemolysins about 2.5 fold. About 90% of cyclophosphamide- rifampicin mutant showed homogenized culture with no auto agglutination but high level of proteases. While, only 10% of cyclophosphamide - rifampicin mutants gave slightly auto agglutination and didn’t produce proteases enzyme. The production of both TCP and CT were increased from rough pigment producing mutant isolates comparing with yellow and smooth mutants.